Various systems and method have been utilized to address the problem of passengers, particularly children, being left unattended in a parked vehicle or gaining unauthorized access to a parked vehicle. Typically, these systems detect the presence of children and provide a warning/notifications. A number of commercially available systems include technology added to existing restraint systems. For example, a weight sensor can be added to a child seat. These systems can include a built-in transmitter for communicating with a key fob and/or other external device via bluetooth/smartphone. Other systems detect the presence of a child/passenger using 2D and 3D cameras, some systems use active electromagnetic methods such as ultrasonics and acoustics, and others include chest clip/buckle sensors/transmitters that detect when the clip/buckle is latched. While these systems have shown the potential to detect the presence of a child seat and classify it as occupied or un-occupied, they are prone to error. For example, clothing, lack of motion of the occupant, and user error can all result in faulty occupant detection. Accordingly, there is a need in the art for an occupant detection system integrated into the child seat operation that is both reliable and does not require a considerable level of effort from the caregiver for proper operation.